Canada strips Viagra patent from Pfizer

Canada's Supreme Court has struck down the patent on global
pharmaceuticals giant Pfizer Inc's Viagra erectile
dysfunction drug and opened the door to generic competition.

The court backed an appeal by Israeli-based Teva
Pharmaceutical Industries Ltd - the world's largest generic
drug maker - which argued Pfizer had been too vague when
filing its patent, which runs out in 2014 in Canada.

In a unanimous 7-0 verdict, the court said Pfizer had not
provided enough details to identify the active ingredient in
Viagra.

"Pfizer gained a benefit from the (Patent) Act - exclusive
monopoly rights - while withholding disclosure in spite of
its disclosure obligations under the Act," Justice Louis
LeBel wrote on behalf of the court.

"As a matter of policy and sound interpretation, patentees
cannot be allowed to 'game' the system in this way ... (the
patent) is invalid."

Pfizer had previously successfully defended patent lawsuits
from Teva in the United States, Spain, Norway and New
Zealand.

"Pfizer expects to face generic competition in Canada
shortly. The company ... is disappointed with the Court's
ruling," the firm said in a statement e-mailed to Reuters.

Company spokeswoman Christina Antoniou, citing commercial
confidentiality, declined to say how much the Canadian Viagra
market was worth.

Pfizer's Canadian patent - which came into force in 1998 -
was divided into seven parts and covered 260 quintillion
different chemical compounds.

But only one of the compounds - sildenafil - was active and
the court said the patent had not provided enough information
to allow another company to produce Viagra.

"Pfizer had the information needed to disclose the useful
compound and chose not to release it," said the ruling.

"Even though Pfizer knew that the effective compound was
sildenafil at the time it filed the application ... it chose
a method of drafting that failed clearly to set out what the
invention was."

LeBel - who said "wilful intent to mislead has not been
alleged or proven in this case" - noted that Pfizer's
submission to the Supreme Court had offered no explanation
for withholding the information.

Teva took the case to the Supreme Court after two lower
courts in Canada ruled against it. No one at the firm was
immediately available for comment.